Process of treating regenerated cellulose articles



Patented July 2, 1935 PROCESS OF TREATING REGENERATED CELLULOSE ARTICLES Julius Voss, Wiesbaden-Biebrich, Germany, assignor to Kalle & Co. Aktiengesellschaft, Wiesbaden-Biebrich, Germany, a corporation of Germany No Drawing. Application March 8, 1932, Serial No. 597,633. In Germany March 10, 1931 4 Claims. (CI. 1848) This invention relates to regenerated celluproduced from ceuui ic s l ti h as 1 lose materials and m e particularly to a process cose, cuprammonium cellulose or cellulose esters, of treating articles formed of regenerated celluare subjected to a treatment whereby the swelllose for the purpose of reducing the we ing capacity or capacity for absorbing water is 5 capacity or pacity for absorbing water. appreciably reduced. The process contemplates Products or articles formed of rege d treating the regenerated cellulose articles with lulose which are obtained, for exa p from a liquid medium comprising an organic solvent cellulose solut such as Viscose, ellprammecontaining water at an elevated temperature.

--- nium, cellulose esters, etc., are characterized in After cooling, the-film is dried. that y Possess a much greater p y for The product of the method just described, 10 water absorption than natural cellulose. For h brought in t t with water, absorbs a many uses this P p is a serious limit o quantity thereof which is considerably less than For example, the ability of artific al threads the quantity of water which the product would formed of regenerated cellulose to Withstand absorb if it were not treated in accordance with washing is considerably lower than that of cotth t t invention ton, and films of regenerate cellulose change As organic solvent constituents of the liquid their dimensions much more With ch g s in medium with which the regenerated cellulose atmospheric humidity than paper films Of 0 1'- articles are treated, all organic solvents which responding size. are substantially neutral, completely or partially Va processes have already been P p miscible with water or capable of being made 26 for overcom ng these disadvantages, but of all miscible with water by the addition of small the suggested methods only that described in quantities of some other organic liquid and German Patent 4 ,7 is the b However, which solvents themselves have no action on the even that method which contempla llbl cellulose or have a slight softening action may be m p d c s of regenerated ellulose to s a utilized. The simple alcohols, such as methyl 25 of a certain de of saturation i an antealcohol, ethyl alcohol, isopropyl alcohol, dioxane, clave at defi temperatures is t t e y diacetone alcohol, monoethyl ether of glycol, may satisfactory and posseses undesirable features. b ti d as in t t examples which In ac a practice, it is extremely difiielllt to a have given satisfactory results. Glycerin and 30 here to the exact Wor Conditions in an ethylene glycol are also suitable butvthe results 30 du y d c q y serious dif culties a produced from the use thereof are not quite as encountered. good as those secured when the substances previ- I have found that the above-mentioned disously mentioned are employed. Instead of a advantages and defects may be overcome and single solvent, a plurality thereof may be used. the swell p y capacity for absorbing Likewise, mixtures of the previously-mentioned wat or Products formed of ated celluorganic solvents with hydrocarbons or other delose may be appreciably reduced by treating the rivatives, such as benzol, may be used if such regenerated Cellulose Products with nic s01- mixtures are miscible to a certain extent with vents containing water at an elevated temperawat r, 40 ture, and preferably in an autoclave. As previously mentioned, the invention con- 40 It therefore, an Object o th s inve t on templates the use of an organic solvent containto provide regenerated cellulose articles characing water. The amount of water present in terized in that the swelling p y o c p y the organic solvent may vary within wide limits.- for absorbing water is appreciably reduced. In the preferred embodiment of the invention,

Another object of this invention is to provide the solvents are used which have a water content a method of reducing the swelling capacity or of from 10% 35% ap y for absorbing water of P s o m The treatment of the regenerated cellulose o regenerated cellulose which pri es t ea article in the organic solvent containing water is i the regenerated Cellulose with rgan c so carried out at an elevated temperature. No prevents containing Water at an va d temperacise elevated temperature is necessary for the 50 ture, and preferably in an autoclave. successful operation of the process. However, I Other objects will appear from the following prefer, in view of the fact that the process is description and appended claims. accelerated at relatively high temperatures to In accordance with the principles or the inutilize a temperature in excess of 100 C. 66 stant invention, regenerated cellulose products The treatment may be effected in any suitable the ' the instant invention, several illustrative examples are hereafter set forth. It is to be understood/that these examples are not intended to limit the invention thereto but are merely to illustrate several specific embodiments which have given satisfactory results.

Example L-A film of regenerated cellulose containing, for example, 16% glycerin and 10% water is heated for 1 hour with 85% ethyl alcohol in an autoclave to 106 C. After cooling, the film is dried.

The product resulting from this procedure when placed in water shows a water content,

after the removal therefrom, of 44%. The film before the treatment just explained, when immersed in water, showed a water content of 62%.

Example II.A film of regenerated cellulose free of glycerin and containing approximately 10% of water is heated to 106 C. for 1. hour with 85% alcohol, and after cooling, dried in any convenient and suitable manner.

The product resulting from this procedure, when immersed in water and removed therefrom, shows a water content of 39%, whereas the film prior to treatment, when immersed in water, showed a water content of 51%.

It is apparent that the treatments considerably decreased the swelling capacity or the capacity of absorbing water.

Example III.A film of regenerated cellulose freed from glycerin, 1 square meter of which has a weight of 55 grams, is heated for 1 hour with ethyl alcohol of strength in an autoclave to 106 C. and then dried. The film before the treatment with alcohol, when immersed in water, showed a water content of 52%.

The product resulting from this procedure when placed in water, shows a water content of only 42.5%. By the treatment of the cellulose with alcohol of 65% its capacity of absorbing water is considerably decreased.

Example IV.A cellulose film containing glycerin is heated to 106 C. with dioxan containing 15% of water or with a solution of 625 cc. of ethyl alcohol or 88% strength, 300 cc. of benzene and cc. of water. The film is then dried.

The treatment with aqueous dioxan or an aqueous mixture of alcohol and'benzene considerably decreases the capacity of absorbing water.

Though the specific examples have been described in connection with films of regenerated cellulose, the invention is not restricted thereto.

The principles of the instant invention are equally applicable-to all types of products formed of regenerated cellulose with or without softeners and with or without modifying ingredients such as, for example, threads, films, tubes, bands, hollow articles, etc.

The results secured by the instant invention are certainly new and unobvious. It is indeed surprising that organic solvents containing water diminish the swelling capacity of products formed of regenerated cellulose, since this process is based on dehydration. It would be thought that the above-mentioned organic solvents would only produce such results when used in an anhydrous state. The contrary was, however, found when solvents of the type previously mentioned were used in the anhydrous state under the same conditions.

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

I claim:

1. A process of reducing the swelling capacity of products formed of regenerated cellulose which comprises heating regenerated cellulose products submerged in a liquid composition comprising an alcohol of the type which is miscible with water and 10% to 35% water to a temperature of not less than C. and thereafter drying the product.

2. A process of reducing the swelling capacity of products formed of regenerated cellulose which comprises heating. regenerated submerged in a liquid composition comprising methyl alcohol and 10% to 35% water to a temperature of not less than 100 C. and thereafter drying the product.

3. A process of reducing the swelling capacity of products formed of regenerated cellulose which comprises heating regenerated cellulose products submerged in a liquid composition comprising ethyl alcohol and 10 o to 35% water to a temperature of not less than 100 C. and thereafter drying the product.

4. A process of reducing the swelling capacity of products formed of regenerated cellulose which comprises heating regenerated cellulose products submerged in a liquid composition comprising monoethyl ether of glycol and 10% to 35% water to a temperature of not thereafter drying the product.

JULIUS VOSS.

cellulose products 

